INTERACTIONS OF TURBULENT JETS WITH TRAVELING SHOCK WAVES

The interaction of turbulent jet with a traveling shock wave has been investigated experimentally in a high resolution large scale shock tube facility. A jet facility has been designed and tested which can supply a flow with a Mach number of 0.9 through a 7.0 mm internal diameter tube exhausting along the center line of the shock tube. Two test flow configurations have been used in these experiments. In the first one, the jet was flowing in the same direction as the traveling shock wave. In the second configuration, the shock was traveling in the opposite direction to that of the shock. Helium, air and Krypton gases were used in the jet flows in an effort to generate baroclinic vorticity through a non-alignment of density and pressure gradients. In all cases, the jet flows were issuing in still air. Extensive flow visualization studies were carried out by using a pulsed planar laser sheet generated by a Nd:YAG laser. The captured images show that the interaction is very complex. A stenosis of the jet has been observed to take place in the near field as a result of the sudden imposition of the pressure behind the shock which is followed by a "wake like" vortex. The field far from the jet exit is characterized by increased turbulence activities. Substantial more mixing has been observed in the case of a Helium jet than in the case of a Krypton jet, as a result of the difference in the generation of additional baroclinic vorticity.

Interaction of a Ms=1.34 shock wave with a MJ=0.9 co-flowing jet. Flow from left to right.

Interaction of a Ms=1.34 shock wave with a MJ=0.9 co-flowing jet. Flow from left to right.

Schematic of the interaction

Schematic of the interaction

: Air-jet interaction with a traveling shock wave in a counter flow configuration. Jet flows from right to left

: Air-jet interaction with a traveling shock wave in a counter flow configuration. Jet flows from right to left